Denmark and Sweden are to boost defence cooperation to counter what they described as a growing threat from Russia, including from “dangerous” fake news campaigns and cyber-attacks, the two countries’ defence ministers have said.

Peter Hultqvist of Sweden and Claus Hjort Frederiksen of Denmark said in a statement before a meeting in Stockholm that Russian hybrid warfare – cyber-attacks, disinformation and fake news – could create uncertainty.

When nations “cannot clearly distinguish false news and disinformation from what is true, we become increasingly unsafe”, the ministers said, adding: “We have both been exposed to forms [of this] and want to better defend our societies in this area.”

This year Stockholm’s Institute of International Affairs accused Russia of using fake news, false documents and disinformation in a coordinated campaign to influence public opinion and decision-making in Sweden.

The study said Sweden had been the target of “a wide array of active measures” including misleading reports on Russian state-run news networks and websites, forged documents, fabricated news items and “troll armies”.

Moscow’s main aim was to “preserve the geo-strategic status quo” by minimising Nato’s role in the wider Baltic region and keeping Sweden out of the international military alliance, the study said.

Hultqvist and Frederiksen said the two countries would also increase more traditional forms of military cooperation, citing the increased presence of Russian naval vessels in the Baltic and airspace violations by Russian military aircraft.

“We already have good cooperation with Sweden and the other Nordic countries, but believe we can expand this more,” Frederiksen said. “We need to stand together when we have an unreasonable Russia moving into the Crimea and building up in our immediate neighbourhood.”

Joint exercises and more cross-border exchanges of military and intelligence expertise would follow, he added.